Unsupportive Husband

I am so sorry if this gets long but I really need some advice and support. My husband has struggled with anger issues our entire relationship (we've been together 6 years). He is mean, angry all the time, degrading and constantly attacks me and our three children. He nags and picks and just keeps going until everyone is wanting to cry. No matter what I say he refuses to see what he's doing he always denies it and says he hasn't done anything wrong. I am 11w2d and I am at such a loss as to what to do anymore. I'm stressed, sad and feeling completely alone. I have barely any support or effort from him whatsoever and I just don't feel like he cares. He's either one extreme or another, and he's famous for sweeping things under the rug, not communicating or being willing to talk things out, and pretending like he has done nothing wrong and I'm the "crazy one" who needs help. Our oldest son, is not biologically his, and he really puts him through hell. I am devistated, as a wife and a mother, trying to protect my children and my own self from a verbally abusive narrcassist. I can't just "up and leave". I've begged him numerous times to seek help in a form of therapy or something and he refuses. I'm not sure how much more I can take.